tests/test-issue4074.t

merge: pass wctx to batchremove and batchget

We would like to migrate direct calls of repo.wvfs/wwrite/wread/etc to a
call on the relevant workingfilectx, both as a cleanup (to reduce the number of
working copy functions on `repo`), and also to facilitate an in-memory merge
that doesn't write to the working copy.

In order to do that, the first step is to ensure we pass the target wctx around
and perform our writes and reads on it. Later, this object might become a
memctx.

#require no-pure

A script to generate nasty diff worst-case scenarios:

  $ cat > s.py <<EOF
  > import random
  > for x in xrange(100000):
  >     print
  >     if random.randint(0, 100) >= 50:
  >         x += 1
  >     print hex(x)
  > EOF

  $ hg init a
  $ cd a

Check in a big file:

  $ $PYTHON ../s.py > a
  $ hg ci -qAm0

Modify it:

  $ $PYTHON ../s.py > a

Time a check-in, should never take more than 10 seconds user time:

  $ hg ci --time -m1
  time: real .* secs .user [0-9][.].* sys .* (re)